The purpose of this project is: to conduct a randomized controlled trial for the treatment of suicidal and self-mutilating behaviors with suicidal patients who have borderline personality disorder (BPD). Suicidal behavior and self-mutilation are two of the most serious problems confronting contemporary psychiatry, but little is known about the effective prevention and treatment of these behaviors. While clinicians have viewed patients with BPD as manipulative and attention- seeking, suicidal behavior and self-mutilation are especially common in these patients and results in significant mortality and costly morbidity. Unfortunately, systematic investigation of the treatment of suicidal behavior and self-mutilation in BPD is sparse. One psychosocial treatment dialectical behavior therapy (DBT), a cognitive- behavioral treatment-has been shown to significantly decrease self- injurious behaviors in BPD. While DBT has become increasingly popular as the treatment of choice for suicidal patients with BPD, there are no replication studies other than the original study conducted by the developer. Our study will be the first large-scale replication of DBT. With respect to medication, studies of fluoxetine, a selective serotonin reuptake inhibitor (SSRI), and other SSRIs have shown their efficacy in decreasing rates of self-mutilation and suicidal ideation in BPD. Furthermore, biological studies of serotonergic functioning in suicide attempters and BPD suggest the potential benefit of SSRIs in treating self-injurious behavior in BPD. Although the combination of DBT and SSRIs has become one of the most common treatments provided to outpatients with PBD, no systematic investigation of the efficacy of combined psychotherapy and medication in BPD has ever been conducted. In this five-year project, we propose to evaluate the efficacy of DBT, SSRI, and combined DBT and SSRI in the treatment of self-injurious behaviors in BPD and to conduct a replication of DBT. We will use a randomized four cell design comparing DBT+placebo, DBT+fluoxetine, fluoxetine+clinical management, and placebo+clinical management. We will conduct this project at the New York State Psychiatric Institute and will have the support of the MHCRC for Suicidal Behavior under the direction of Dr. J. Mann. Over a 5 year period, 180 subjects with BPD will be randomized to 12 months of treatments and a naturalistic follow- up at 12 months.